Why is the bar pendulum called a compound pendulum?

Answer: Bar pendulums are compound pendulums because they include extended mass, just like a revolving bar. The most straightforward kind of compound pendulum is a bar pendulum. It has pores punched evenly throughout its lengths in the shape of a rectangle bar.

It has holes equally placed across its lengths and is shaped like a rectangular bar. A metallic bar that is one meter long makes up the bar pendulum. A sequence of circular holes, each measuring about 5 mm in diameter, are bored down the length of the bar. Every slot can accommodate a vertical knife edge, which halts the bar.